Inherent and multiple strain hardening imparting synergistic ultrahigh strength and ductility in a low stacking faulted heterogeneous high-entropy alloy
Inherent and multiple strain hardening imparting synergistic ultrahigh strength and ductility in a low stacking faulted heterogeneous high-entropy alloy
复制标题
固有和多重应变硬化赋予低堆垛层错异质高熵合金协同超高强度和延展性
DOI：
10.1016/j.actamat.2022.118516
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发表时间：
2023
期刊：
影响因子：
9.4
通讯作者：
Han Xiaodong
中科院分区：
文献类型：
--
作者：
An Zibing;Mao Shengcheng;Liu Yinong;Yang Luyan;Vayyala Ashok;Wei Xiao;Liu Cheng;Shi Caijuan;Jin Huixin;Liu Cuixiu;Zhang Jianxin;Zhang Ze;Han Xiaodong
具有高屈服强度和延展性的合金具有降低质量、节约能源和提高结构可靠性的潜力，因此具有广泛的应用前景。然而，提高强度通常是以牺牲延展性为代价的，这通常被称为金属合金的强度-延性权衡。在这项工作中，我们探索了在CoCrFeNiMn FCC高熵合金中使用非均质晶粒尺寸结构和降低层错能的策略，以克服这种权衡的局限性。通过这种方法，合金的屈服强度为980 MPa，抗拉强度为1385 MPa，抗拉伸长率为48%，这得益于异质变形诱导（HDI）硬化、变形孪晶、Frank-Read位错源和由这些组织引发的lomo - cottrell位错锁等多种机制的协同应变硬化。这些微观变形机制通过位错平均自由路径的原位细化帮助合金硬化。
Alloys with high yield strength and ductility are attractive for application because of their potential to offer mass reduction, energy savings, and enhanced structural reliability. However, increasing strength usually comes at the expense of ductility, which is commonly known as the strength-ductility trade-off for metal alloys. In this work, we explored a strategy of using a heterogeneous grain size structure and a reduced stacking fault energy in a CoCrFeNiMn FCC high entropy alloy to overcome the limitations of this trade-off. By this approach, the alloy achieved a yield strength of 980 MPa, a tensile strength of 1385 MPa, and tensile elongation to failure of 48% benefiting from cooperative strain hardening via multiple mechanisms, such as hetero-deformation induced (HDI) hardening, deformation twinning, Frank-Read dislocation sources and Lomer–Cottrell dislocation locks instigated by such structures. These micromechanisms of deformation help to harden the alloy via in situ refinement of the mean free paths for dislocations.